In order to extend the service life of asphalt pavement, various methods have been introduced until now, wherein a method using a chemical modifier and a method using a geogrid are representative methods.
The method using the chemical modifier is a method in which viscosity of an asphalt binder increases by melting petroleum-based (SBS or SBR) polymer particles in the asphalt binder. This method exhibits an advantageous effect on rut resistance of an asphalt mixture at a high temperature, but is difficult to be practically applied since problems of excessive costs, difficulty in quality control, increase in energy costs according to increase in a temperature for producing a mixture, early loss of a polymer network structure by high reactivity with oxygen due to an existing unsaturated carbon double bond (C═C) in the styrene or polybutadiene segment, the possibility of cracking by an increase in fragility of a material at a low temperature and the like are accompanied.
And the method using the geogrid is a construction method in which geotextiles woven in the form of a grid are installed in places. This method exhibits advantageous effects of increasing reflective cracking resistance performance from a lower layer and rut resistance and the like, but there are weak points such as a construction period is prolonged since a construction process is complex, construction costs increase, and also when the highest stress concentration or shear deformation occurs inside 3 to 5 cm of a surface layer from an upper surface, actions therefor cannot be taken.
Besides, when bicomponent conjugated fiber for a hot asphalt (Korean Patent No. 10-0933302) is used in a reinforcing method using reinforcing fiber, in a process for injection production by mixing a polypropylene (PP) and polyethylene terephthalate (PET) resin having different melting points from each other, there are problems such as: increased costs due to increased loss of raw materials because of frequent fractures in fibers caused by resins exhibiting different elongations; a serious balling phenomenon in which fibers are entangled when mixed; and a great difficulty of injecting fiber manually at a hot-mix asphalt mixture plant.